The present invention relates to a computer-human interface device, and more particularly it relates to a stylus coupled to a supportable mechanical linkage for providing and receiving commands to and from a computer.
As the use of Computer Aided Design (CAD) Systems becomes more widespread, the need for cursor and command control devices which accurately and easily track three-dimensional position or motion is also growing. Devices which allow users to control a cursor with three-dimensional position and/or orientation commands are available for various applications. Among them are many hand-held input devices which allow users to interact with a host processor by controlling the position of a cursor or manipulating graphic objects on a computer screen. While these devices allow three-dimensional information to be transmitted to a computer they do not allow the user to use gestures and motions which are natural to the user.
For example, a prior art device of the type which is used for three-dimensional control involves the use of accelerometers to transduce the position and orientation of a stylus in space as described in U.S. Pat. No. 4,839,838. This device makes no provisions so the stylus can be grasped in a manner which makes use of finger dexterity nor does it include mechanical support to reduce fatigue or enhance user control or dexterity.
Another prior art example is an ultrasonic position-locating device like the one shown in U.S. Pat. No. 5,142,506. This device transduces position and orientation by triangulating ultrasonic signals. As with the prior art previously described, this device uses a free-floating stylus which includes no provisions for mechanical support to reduce fatigue or enhance user control or dexterity. Furthermore, this device is used with a stylus that is grasped in the palm of the hand. The use of such a stylus precludes fine positioning with the fingers and greatly reduces the dexterity of the user to manipulate position and orientation. In addition, this device is used with digital buttons on the stylus to send to the computer command signals. A button of this type is commonly called a xe2x80x9cclickerxe2x80x9d on a xe2x80x9cmouse.xe2x80x9d Because such buttons are mechanically coupled to the free-floating stylus, it is difficult to push the buttons while maintaining the position and orientation of the stylus. By pushing down on the button, the user will necessarily move the stylus from its desired position. Accordingly, these commands are difficult to control under many circumstances.
In the present invention, the user holds a stylus which is supported by a support apparatus on a fixed surface so that the user can easily manipulate the stylus in free space to interact with a computer. The three-dimensional motion of the user is translated through the stylus and mechanical linkage to a processor which communicates with the computer, thus allowing commands to be sent to the computer which track the three-dimensional motion of the user. Therefore, cursor control in three-dimensions on the two-dimensional computer screen is possible.
In one embodiment, the stylus is supportable on a fixed surface by a set of mechanical linkages which include individual components joined together by a sufficient number of joints to allow several degrees of freedom in the motion of the stylus. These mechanical linkages provide mechanical leverage, friction, counter-weighing, and/or spring resistance in order to reduce fatigue of the user and to provide support to enhance the stability and dexterity of user manipulation of the stylus.
An embodiment of the present invention includes computer software and hardware which will provide force feedback information from the computer to the stylus. The computer sends feedback signals to the mechanical linkage which has force generators for generating force in response to images depicted on the computer screen. Incoming commands from the host computer are monitored by the microprocessor and instruct the microprocessor to report forces felt by a joint or set forces on a joint of the mechanical linkage.
In the aforementioned embodiment of the present invention, the joints of the mechanical linkages are coupled to sensors which provide information about their position. Such information is transmitted to a microprocessor so that position and orientation of the stylus can be computed using kinematic equations associated with or related to the particular linkage system. In another embodiment, position and orientation of the stylus is sensed through the use of ultrasonic, magnetic, or optical position and orientation sensors mounted on the stylus.
Another aspect of the present invention includes a remote control unit which is used in place of a command clicker on the stylus. For example, a foot pedal or hand-held unit for the user""s opposite hand is included to provide command control to the computer. Accordingly, manual dexterity of stylus manipulation is not compromised.